In the case of applying a so-called shingled write (also referred to as shingled recording) method in a magnetic disk device (hereinafter referred to as hard disk drive (HDD)), the track group (hereinafter referred to as a band) is limited to be divided within the same ZONE/HEAD (hereinafter referred to as ZONE/HEAD) in order to keep the transfer rate constant in the same ZONE/HEAD. In addition, retry management at the occurrence of write/read error is also managed on the assumption that it is within the same ZONE/HEAD.
In the shingled recording system, there is a Zoned device ATA Command set (ZAC) standard to improve a point of weakness in random access and a point which is difficult to use. In the ZAC standard, the entire device is divided by a uniform number of sectors (capacity), and the size and boundary are presented on the host side. Although this makes it possible to use the device easily, the device is required to have an extra capacity.
In other words, as in the ZAC standard, when the device is created such that the band of the whole region is a fixed band of the same number of sectors (capacity) specified, a fractional track that does not satisfy the band size takes place near the ZONE boundary. Thus, in order to satisfy the required capacity, the ZONE boundary is moved toward the inner circumference by the necessary number of tracks to create a band, or the ZONE boundary is conversely moved toward the outer circumference to incorporate the fractional track into the next ZONE. In addition, if it is not desired to move the ZONE boundary, the fraction track is used as a spare sector (for a substitute when a defect occurs) which is not included in the user capacity.
When moving the ZONE boundary, it is necessary to extract defects of the region (because the Bits Per Inch (BPI) differs if the ZONE changes). Thus, there is a problem that the HDD manufacturing process is prolonged. Further, when the spare region is used, there is a problem that the device capacity is reduced.
An object of the embodiment of the present invention is to provide a magnetic disk device and a recording method which is capable of reducing waste of the capacity due to the zone boundary when performing the shingled recording system, eliminating the need to extract defects in the zone boundary, and shortening manufacturing process time.